Depending on where this is posted will determine how many chain of command slots (this was at a hospital so it will have the hospital staff in there as well but starting at a company level it generally goes company- battalion- brigade- division- corps- department of the Army, DoA is where potus, SoA, joint chef of staff, etc fall under, also for every commander (commissioned officer) there is a NCO support channel that works next to the officer kinda as a advisor if you will to make sure or supposed to ensure mission success as well as having the enlisted troops best interest. Guess kinda to keep the officers in check. The chain of command can also go as far as if you are tradoc or frocom, then you have special operations command so on and so on, also depending on your job you have a co and sgm at the top for each "field " so infantry, engineers, chemical, and so on. I've seen units post the minimum and some post them all. But where I took the photo is where the new recruits sets,(its a tradoc base) so I would assume it would stay current because of thr fng always seeing it.